An example of such a concept is the patent EP 594 699 B1 (Ehlerding). The said patent proposed to use parallel oriented, actively superimposed axle arrangements in order to allow the high acceleration of light-weight, short-range axles in the entire working space of less acceleratable long-range axles in machine tools that are preferably designed for processing two-dimensional or flat workpiece in two or three axes oriented orthogonally relative to one another.
From this publication is it known that shorter partial axles, called additional axles here, can be carried by a gantry movable over the material and having a motion unit carrying the additional axles, which motion unit in turn moves along the gantry, or the material also can be moved by means of base axles, in which case a tool is able to move by means of additional axles, again independently of the movement by the base axles, relative to the material. It is just as conceivable to move one or more tool-carrying additional axles along a fixed gantry, as a base axle, over the material, whilst the material is moved along and beneath the gantry by means of a further base axle oriented orthogonally to the gantry.
It is common knowledge that instead of a gantry also a cross member or a movable or stationary arm or extension arm having a mobile or stationary bearer may serve as the support for additional axles, and that notwithstanding the conventional case, in which the base axles preferably move the heavy machine parts or the heavy material to be measured or processed in the horizontal plane, all the said axle configurations may also have a different orientation in space. Instead of the measuring devices or tools, a lightweight or small material to be measured or processed can be carried by the additional axles and by joint movement of base and additional axles can be guided along measuring devices or tools without a fundamentally different co-ordination being required for this.
Furthermore, it is known, for example from WO 2006/75209 A2 (Gattiglio et al), that additional axles may indeed be physically oriented orthogonally relative to one another and move jointly in a plane that is aligned with two base axles, but so that in this plane of movement the physical additional axles are not oriented parallel to the base axles, for example, as in WO 2006/75209 A2, rotated through 45° with respect to the base axles in the common plane of movement.
A redundant, parallel oriented action of the axles is basically also easy to implement here, as the fixed transformation required for this between the alignments of two Cartesian co-ordinate systems oriented to the physical axial directions is to be provided by means of very simple, constantly-acting analogue, digital or computer-generated multiplication elements without any problems for the average person skilled in the art.
Furthermore, it is known from the prior art that instead of linearly moved additional axles, it is also possible to use devices rotatable through a usually small angular amount, so that by means of an adequate distance between centre of rotation and measuring or processing point, a sufficiently approximately linear movement of the elements of a measuring device or a tool relevant to the measurement or processing occurs. A variant of this is used when bundled radiation energy, mainly a laser beam, is directed by means of pivotable mirrors or other deflecting elements onto a processing point. Additional axles in this sense are dealt with in detail for example, in the document WO 96/29634 A1 (Cutler et al), see in this context the illustrations in particular of FIG. 2 and FIG. 4 of that publication. Similar mechanical conditions pertaining to the additional axles are also possible for other tools, for example, rotatable milling heads, or corresponding measuring devices, in which case often additionally a movement along the tool axis or, for example, a measuring sensor axis is possible, also for compensating for the variation from a movement exactly parallel to the particular base axle.
The patent specification EP 1 294 544 B1 (Sartorio) discloses a further configuration and as an improvement over the prior art proposes a parallel kinematic combination, linearly movable in two axes, of the highly acceleratable additional axles, which in particular gives rise to the advantage that in the two horizontal main directions of movement of a machine designed in this manner the kinematic conditions are in this respect comparable, which can improve the efficiency of a two-dimensional tool movement.
Little is disclosed about the practical co-ordination of the simultaneously driven axles, however. Only a few essential general requirements are mentioned, which are intended to apply to the coordination of the partial axles. EP 1 294 544 B1 provides some information about this from paragraph [24] to paragraph [39] of the description and in the main claim. The only information that can be derived from this section of the description teaches us that the maximum speed of the base axles has to be substantially higher than the tool speed, and that from the said conditions and the assumption of known machine data it is possible to set up the necessary equations to determine the as yet unknown machine data.
Evidently based on this still incomplete teaching, EP 1 758 003 A1 (Cardinale et al) proposes first a co-ordination of the axles, which according to the principle of inverse kinematics is intended to make optimum use of the redundant degrees of freedom of a motion mechanism by applying a special form of what is known as the Jacobi matrix. All the remarks relating to this are kept so general that it does not even become sufficiently clear just how important specific limiting conditions in such a process would be, let alone what conditions would be essential for this in order actually to obtain unambiguous solutions of practical use for co-ordination of the axles. Nor is a specific reference to this made in the further description, the examples and the claims, although, for example, basically in all of the adequately substantiated application examples, in particular also in the case of the laser cutting machine concerned, a corresponding explanation would be possible, even if not necessary. To the extent that this ought to serve, for example, also for rotatory axles or even redundantly operating rotatory axles, in order to indicate that the claimed invention can also be adapted to complexly configured systems, then this has not been done in a manner that allows an adaptation at all, without further inventive steps. Compared with the known prior art, in point of fact nothing is disclosed that the skilled person would not already know. Firstly, a distribution of movement to redundantly operating axles by filtering is not in any way an innovation, and the fact that as this happens the additional axles (are intended to) execute as their movement the difference between the total movement and the movement of the base axles, is not really unexpected. Otherwise, the publication if anything repeats what could basically already be read in EP 1 294 544 B1: the maximum speed of the base axles should be selected to be clearly higher than that of the additional axles. (See EP 1 758 003 A1, description, paragraph 32 and claim 9).
As far as specifically comprehensible at all, since it also remains unclear how not only acceleration or amplitude components of a movement but equally whole contours or individual sections shall be “filtered”, this teaching ultimately corresponds only to the prior art, for example, from EP 594 699 B1, albeit in an expansion of the claims to virtually every kind of controllable physical variable, which need not be of further interest here.
Nevertheless, it is listed as prior art here because it documents the prior art precisely by way of example with respect to one of the problems to be solved, that is to say: one aspect of the present invention also to be described here is how the efficient execution of movement by additional axles can be especially efficiently co-ordinated at a number of relatively small contours within a more comprehensive overall processing. EP 1 758 003 A1 proposes for this purpose to “filter” this movement, which does not represent a reproducible technical teaching for inherently closed contours, but in conjunction with the use of synchronously redundantly operating axles does show very clearly the need for a corresponding solution, which would be as generally applicable as the word “filter” sounds and at the same time offers an efficient co-ordination of the axis movements.
A relatively simple possible variant to this, but which is less suited to using the potential of synchronously redundantly operating axles since it relates expressly to an alternating use of base and additional axles, is described in EP 1 366 846 B1 (Leibinger et al). See in particular FIG. 9 there.
Correspondingly, according to the prior art it is assumed that the skilled person knows how a discrete contour within an overall processing operation is distinguished, identified, and dimensionally determined.
In actual fact, a large number of variants in this respect are known to the skilled person or are easily conceivable, which mainly ultimately add up to an at least simplified preliminary simulation of the machining, which determine the position and dimensions of individual closed trajectories by means of minimum and maximum value acquisitions in all relevant machine axes and allocate the data thus obtained, for example, by means of a special code or as an annotation, to the generated CNC program of a specific section. In exactly the same way it is also possible for such steps within a preliminary processing to take place initially in a control system, where the values obtained are then mostly only temporarily filed and used in the memory of the control system. The fact that corresponding data about separable contours can be present may therefore, according to the prior art, be taken for granted.
But although it easily becomes plain how the co-ordination of the base and additional axles in EP 1 366 846 B1 may be envisaged, in EP 1 758 003 A1 this remains entirely shrouded in mystery in respect of individual contours, unless one assumes that the process concerned is similar to that in EP 1 366 846 B1, that is, 1. identification of a suitable partial contour, 2. optional positioning of the base axles to a suitable starting position, 3. execution of the identified partial contour by means of the additional axles. If, in addition, a coordinated motion, superimposed for reasons of efficiency, to and from these identified partial contours is provided, that is, in such a way that also a readjustment of the additional axles to their respective starting position, or perhaps also the start or the remainder of a processing procedure by means of or with the aid of the additional axles is performed, even while the base axles are moving, this can surely not be regarded as reproducibly paraphrased for the skilled person with the use of the term “filtering” and vague indications that one can use the Jacobi matrix if problems arise—quite apart from the question of novelty.
In a recently filed patent application of the applicant of the present invention, a variant of redundant axle arrangements having a translatory action is described, which basically does not require an identification of such partial contours to be handled by the additional axles, since by means of the proposed design of machines or a corresponding method, any contour can be worked off at the maximum possible acceleration of the additional axles without any differentiation being required (hereafter called Method 1).
A further previously filed patent application of the applicant of the present invention describes a method of achieving at least a considerably improved suitability of the additional axles with a maximum acceleration also for less conveniently designed machines. This method for optimizing axle co-ordination also manages without the division of a total measurement or processing operation into separate partial contours (hereafter called Method 2).
But, in contrast to Method 1 (which is not applicable to every machine or not always with the necessary speeds), the co-ordination of the axles for any contour with virtually equal efficiency cannot be achieved with Method 2. In particular when many relatively small partial contours are distributed over a relatively large surface, an automatically highly optimized co-ordination of the axles can generally not be guaranteed with Method 2, so that even the very much simpler method from EP 1 366 846 B1 may in such specific cases be at least similarly efficient. But these two methods (Method 2 and EP 1 366 846 B1) come off especially badly where a lot of contours to be dealt with separately are arranged close together, as Method 2 is unable to identify and deal with these contours with discrimination and EP 1 366 846 B1 is unable to co-ordinate the frequent position changes of the base axles in time with a kinematically quite possible beginning or end of a partial treatment.
Even though the superimposition of two basic movements, for example, the continuous application of a contour during a simultaneous uniform transport movement, is very well known from the prior art, this can as such be employed relatively straightforwardly only when the time of the individual contour treatment by means of additional axles, for example, of a laser scanner for engraving, is very brief compared with the passage of the corresponding region through the movement range of the additional axles. The superimposed rapid movement can then be synchronized with the constant main movement—a completely normal process, the application of which nevertheless does need special preliminary planning.
What is required in the case of the present problem, however, corresponds to a virtually uninterrupted throughput of parts with different engravings, with different time requirement and in different sizes, the transport movement in turn having to be matched thereto to the point of the temporary reversal of movement—and all this usually in two dimensions—that is, something which cannot be integrated in an orderly manner, even by the experienced expert, from the currently available modular automation systems of modern control systems. A corresponding versatile solution is as yet unknown.
Besides these limitations of an optimum movement coordination at numerous closely located small partial contours, yet a further problem exists for many measuring machines or machine tools having redundant axles with a translatory action: the background art, to the extent that the underlying problem is dealt with at all, assumes that after every highly accelerated movement the additional axles that are correspondingly leading are eventually overtaken by the base axles again, so that the additional axles are located in their starting position again, usually in the middle of their respective movement range. In particular for such mechanical configurations, in which one or more additional axles are moved by one or more base axles over a surface to be measured or processed, for example, by means of a gantry, there consequently occurs at the edge of the total movement range a region of about half the width of the movement range of the additional axles that normally cannot be reached, so that, for example, a gantry or its range of movement has to be correspondingly wider in order to utilize substantially the same working space as without additional axles.
Consideration has not yet been given to the fact that during a co-ordination movements according to the prior art the base axle swings out as it were beyond the position to be approached, so that a completely reliable function of a machine coordinated in this way is possible only within a range that corresponds overall to the movement range of the base axles less twice the movement range of the actual additional axles. This is explained by the fact that during a movement to an edge of the movement range, in each case the movement range of an additional axle in the opposite direction is needed to compensate for the braking response, so that, for example, the tool is then positioned momentarily at the edge of the additional axle that is located opposite the outer limitation. At the end of the movement, the base and additional axles then balance each other out, i.e. the base axle comes back from the edge so that the additional axle is able to move into its starting position again, whilst the overall position in this axis remains constant. Momentarily, therefore, on each side of the total movement range of base and additional axles allowance is to be made for a “run-out zone” of approximately the movement range of the additional axle, which cannot be utilized as a measuring or processing area. As most additional axles for synchronous redundantly active operation according to the prior art required only a relatively short movement range, this was at best a rather minor problem. But since, however, commensurate with development over recent years, it is becoming increasingly accepted that a relatively large minimum movement range is necessary for an efficient redundantly effective operation, the solution to this sub-problem of overall co-ordination now also has greater relevance.
It is therefore the technical problem of the present invention to avoid the disadvantages of the known movement co-ordination methods for redundant axles having a translatory action of a measuring machine or machine tool and to disclose a co-ordination method that provides an opportunity for the movement range of base and additional axles to be fully utilized even during continuous superimposed movement of the redundant axles and, appropriately modified, also further improves the other movement co-ordination, in particular during processing of numerous closely consecutive, relatively small, separate partial contours.